Comparison of yields and biological nitrogen fixation of two legumes grown in different silt soils

摘要

The legume species usually sown in mixtures with grasses do not grow very well in silt soils. Biological characteristics of birdsfoot trefoil (Lotus corniculatus} and alsike clover (Trifolium hybridum) are still poorly documented, though they can resist drought and/or water excess. We compared, (i) early development, and (ii) biological nitrogen fixation by four varieties of each species grown in silt soils. Four varieties of birdsfoot trefoil and of alsike clover were sown without inoculation in 4.51 pots filled with five different silt soils (n = 4). At the end of the experiment, above-ground plant parts were counted, measured, dried, weighed and prepared for ~(15)N:14N measurements. Within each species, the number of leaves and ramifications, leaf area, and dry weights did not differ between varieties. Conversely, results differed markedly between soil types. Nodules were found in all pots, but there were significant differences in the amount of fixed nitrogen among soils in birdsfoot trefoil as well as in alsike clover: the proportion of the plant N derived from fixation varied from 0 to about 80%.